IL 13rs20541 single nucleotide polymorphism and serum IL -13 level in children with bronchial asthma

Abstract

Background: Bronchial asthma is a common respiratory illness affecting adult and pediatric populations. Interleukin (IL)-13 is a central  key mediator of allergic inflammation, and it plays a pivotal role in the pathogenesis of asthma. Several studies revealed that genetic  variants of IL-13 promoter rs1800925 allele play a role in asthma severity. We sought to investigate the role of IL-13 rs20541 single  nucleotide polymorphism (SNP) and serum IL - 13 level in relation to asthma severity in a group of asthmatic children .

Methods: This controlled cross-sectional study included 80 participants: 40 apparently healthy controls and 40 asthmatic children,  subdivided into three groups: mild (n=12), moderate (n=18 cases), and severe (n=10), recruited from Pulmonology Unit, Children’s  Hospital, Ain shams university. Characterization of IL-13 rs20541 SNP was achieved by TaqMan real-time PCR. Serum IL-13 concentration  was measured using a commercial sandwich ELISA assay.

Results: The dominant genotype as regards IL-13 rs20541 SNP among patients  and controls was GA (60% and 92.5%, respectively). G and A allele frequencies between patients and controls differed significantly (p  =0.002) as the dominant allele in the control group was G allele (70.0%), versus the A allele in the patients’ group (53.8%). Patients had  statistically significantly higher levels of IL-13 compared to controls (median= 45 pg/ml versus 4 pg/ml; p<0.001) Serum IL-13 correlated  positively with IgE levels and was able to discriminate between patients with severe asthma and those with mild to moderate asthma at  cut off value of >83 pg/ml (sensitivity 90%, specificity 90%, positive predictive value 96.4% and negative predictive value 75%).

Conclusion:  IL-13 rs20541 SNP polymorphism is associated with asthma in Egyptian children, while serum IL-13 is linked to the severity  of asthma.